In the gas transportation and transmission fields, commonly multiple samples are extracted from a source (pipeline, tank, etc.) at certain times or at certain locations in order to assess its quality and energy content of the gas. Typically, in the context of LNG, the sample acquisition process is automatic and involves storage in discrete cylindrical sample containers for later, periodic scheduled collection by a field worker of multiple sample cylinders. The sample collection process and location of the sample cylinders preferably occur in the same environmentally controlled cabinet employed for conditioning of the LNG for sample collection such as those structures described in Applicant's U.S. Pat. Nos. 7,484,404 and 8,056,399, the subject matter of each being incorporated herein by reference.
Preferably, the cabinet structures are flammable/explosive and are constructed to conform to National Electrical Code Class 1, Division 1, Groups C and D with a T3 maximum temperature rating for North America are or with international standards such as ATEX and IEC Zone 1. Commonly, such cabinets are remotely located from the facility with instrumentation, e.g. chromatographs, employed for gas analysis. Consequently, the collection of sample cylinders requires a field worker to access the cabinet interior and swap out the full sample cylinders for new, empty cylinders. Once the full cylinders are removed from the cabinet they are taken to a facility for later analysis. Typically, a single cabinet may include several sample cylinders.
In these cases, a field worker must close the isolation valves for each cylinder and undo the mounting bracket in order to remove the sample cylinder from the cabinet interior. The undoing of a cylinder clamp and re-clamping a new sample cylinder requires the use of both hands and entails considerable effort and time. Because of the flammable/explosive content in a filled sample cylinder, particularly in the case of removal, the field worker must exercise considerable care. Where two hands are required to loosen and unclamp a filled sample cylinder from its mounting bracket, the lone field worker management of the sample cylinder is hampered when it is desirable to maintain a firm grip on the sample cylinder during the removal and substitution process. Consequently, additional assistance or an alternative adjunct to retain the now-loosened cylinder in the mounting bracket may be needed.